KR19990077545A - Double side grinding apparatus and double side polishing apparatus - Google Patents

Abstract

It is a double head grinding device and double head grinding device that can raise the accuracy of deflection and reduce the pitching error, improve the positioning accuracy and secure the rigidity against the processing reaction. A plurality of guide surfaces 14a, 14b and 14c for supporting and moving the main shaft 13 are formed, and a driving point synthesized by the plurality of guide surfaces 14a, 14b and 14c is the main shaft 13. Double head grinding machines or double head grinding devices coinciding with the center of the head. Since the number of guide surfaces is three, since it does not interfere with carrying in / out of a workpiece, it is preferable.

Description

Double head grinding device and double head grinding device {DOUBLE SIDE GRINDING APPARATUS AND DOUBLE SIDE POLISHING APPARATUS}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a double head grinding device suitable for simultaneously grinding both end faces, or a polishing device suitable for simultaneously grinding both end faces, for a workpiece that requires a plan view and parallelism of both end faces.

In the workpieces applied to semiconductor silicon wafers, optical components, CDs, MDs, and the like, the surface planarity and parallelism of the surface thereof are urgently required, and the solutions are becoming stricter as the years are repeated. Background Art Conventionally, a double head grinding device has been known as an apparatus capable of simultaneously grinding both end surfaces of a workpiece requiring a plan view and parallelism of both end surfaces with high efficiency. The finished precision of the workpiece | work processed with this double head grinding apparatus is generally about several micrometers in both plan view and parallelism.

1 is a front view of an example of a conventional lateral double head grinding device, and FIG. 2 is a side view thereof. The two-head grinding device of FIGS. 1 and 2 moves so as to be able to contact both sides of the workpiece 2 simultaneously with two open sides of the cup-type grinding wheels 1a and 1b having a flat grinding operation surface in the cross section. Double head grinding device arranged for grinding operation.

In the double head grinding device of FIGS. 1 and 2, a relative rotational movement is given to the main shaft by the main shaft motor, the center of rotation is the same, and each tip of the two main shafts 3a and 3b facing each other. The cup grinding wheels 1a and 1b are detachably attached to each other, and the grinding operation surfaces of the cup grinding wheels 1a and 1b face each other. Each of the main shafts 3a and 3b is constrained by a slide or rolling guide 4. The guide 4 is fixed on the bed 8, and in the case where the double head grinding device is horizontal, it is usually located below the main shafts 3a and 3b and parallel to the central axis of rotation of the main shafts 3a and 3b. Two are arranged.

The rotational force of the main shafts 3a and 3b is transmitted through the transmission belt by the main shaft motor 5 disposed above the main shafts 3a and 3b. In addition, although the horizontal double head grinding apparatus is shown in FIG. 1, the vertical double head grinding apparatus also has a similar structure arranged in the longitudinal direction.

In the conventional double head grinding device, rolling bearings are used to rotate the main shaft. In order to secure the rotational accuracy of the spindle, angular contact ball bearings are placed facing each other, and preloaded or tapered roller bearings are used to secure rigidity. Even by these means, 1 kg in precision and 20 kgf / m in rigidity is a normal limit.

In the conventional double head grinding device, a slide guide surface is often used for the guide in consideration of damping property. However, when the microscopic movement is performed with a positioning accuracy of 1 µm or less, the guide slips. (stick slip) occurs and this causes a pitching error in the grinding surface.

In addition, in the conventional double head grinding device, as shown in Fig. 2, the machining point 7 and the guide 4 on the grinding operation surface of the cup-type grinding wheels 1a and 1b, as well as the center of the driven part, are shown. As the distance from the center of motion 6 as a distance and the diameter of the main shaft (3a) (3b) is larger, there is a tendency that their distance is widened, and this trend increases as the workpiece is enlarged. However, when the distance between the machining point 7 and the guide 4 surface or the center of motion 6 becomes long, it becomes difficult to secure the rigidity, and there is a problem that measurement errors due to errors of Abbe occur. .

On the other hand, in recent years, for example, in glass of optical parts, semiconductor silicon wafers, and the like, the demand for the finished precision of the processing surface has become stricter as the years go by, and as the workpieces such as silicon wafers have increased in size, the grinding apparatus does not increase in size. There is no way. In order to achieve a depth of 10 nm in submicron and surface roughness in the flatness with respect to the finished precision of the workpiece by the grinding method using a double head grinding device, It is necessary to have sufficient rigidity for the reaction force.

Therefore, the present invention provides a double head grinding device capable of eliminating or suppressing the above problems, and in detail, increases the accuracy, reduces the pitching error, increases the positioning accuracy, and secures the rigidity against the processing reaction force. It is an object of the present invention to provide a double head grinding device and a double head grinding device.

1 is a front view of an example of a conventional lateral double head grinding device;

Figure 2 is a side view of an example of a conventional lateral double head grinding device,

Figure 3 is a perspective view of one example of the double head grinding device of the present invention,

Figure 4 is a side view of an example of the double head grinding device of the present invention,

5 is another embodiment of the double head grinding device of the present invention.

<Description of Symbols for Major Parts of Drawings>

1a, 1b, 11a, 11b: Cup-type grinding wheel 2, 12: Workpiece

3a, 3b, 13: spindle 4: guide

5a, 5b: Spindle motor 6: center of motion

7: machining point 8,17: bed (base)

14a, 14b, 14c, 14d: guide surface 15: saddle

16: headstock 18: guide surface member

In order to solve the above problems, the double head grinding device or the double head polishing device of the present invention contacts the machining operation surfaces of the grinding wheel or polishing cloth mounted on two opposing spindles to contact both end faces of the workpiece, A device for simultaneously grinding or polishing the front and back surfaces of a workpiece by rotation of the workpiece, and a plurality of guide supporting mechanisms for supporting and moving the main shaft are formed and synthesized by the guide surfaces of the plurality of guide supporting mechanisms. The center of motion as the center of the drive member is substantially coincident with or completely coincides with the center of the main shaft.

According to the present invention, since the center of motion synthesized by all the guide surfaces substantially coincides with or coincides with the center of the main shaft, it is close to the machining operation point of the double head grinding device or the double head polishing device.

Therefore, the bending component of the main shaft can be made small among the reaction forces when the workpiece is ground by the main shaft, thereby making it easy to secure the rigidity against the processing reaction.

In the double head grinding device or the double head grinding device of the present invention, the number of the guide surfaces is three or more, which is necessary to match the center of motion of the guide surfaces with the center of the main shaft. In order not to obstruct, three guide surfaces are most preferable.

In the case where three guide surfaces are used with the double head grinding device or the double head polishing device as a horizontal type, the arrangement of the guide surface and its supporting mechanism is preferably the following combination. The first combination is a combination consisting of two guide surfaces disposed on the horizontal plane below the main axis and one guide surface disposed above the main axis. The second combination is a combination consisting of two guide surfaces disposed on the horizontal plane above the main axis and one guide surface disposed below the main axis. In any case, it is preferable that the three guide surfaces and the supporting mechanisms are arranged in a triangular or equilateral triangle, and the main axis in the geometric center position. The double head grinding device or the double head polishing device of the present invention having such a configuration is not limited to the horizontal type, and the arrangement of a plurality of guide surfaces can be applied to the vertical type as well.

The plurality of guide surfaces in the double head grinding device or the double head polishing device of the present invention may be formed by at least one guide surface member integrally formed with a bed, a column, or the like.

The guide mechanisms of the plurality of guide surface members disposed in the double head grinding device or the double head grinding device of the present invention may include different types. In particular, when applied to a horizontal double head grinding device or a horizontal double head grinding device, the guide mechanism of the guide surface disposed above the main shaft is preferably a static pressure guide mechanism, and the guide surface of the guide surface disposed above and below the spindle axis. It is also possible to divide and combine the types into a static pressure guide mechanism and a slide guide mechanism.

An example of the double head grinding device of the present invention is shown in FIG. 3 as a perspective view and in FIG. 4 as a side view. In the two-head grinding device of FIGS. 3 and 4, the two open sides of the cup-shaped grinding wheels 11a and 11b having a flat grinding operation surface on the end face of the main shaft 13 are faced to each other on both sides of the workpiece 12. FIG. Two main shafts 13 are disposed to face each other so as to be movable in contact with each other and to perform a grinding operation. The main shaft 13 is integrally fixed by a saddle 15 to form a main shaft 16.

Two slidable guide surfaces 14a and 14b are fixed to the bed 17 so as to fit on the same horizontal surface and the lower surface of the headstock 16, and each guide surface 14a and 14b. The guide mechanism is a V-shaped slide guide mechanism. The upper surface of the headstock 16 is formed to fit the guide surface 14c above the guide surface, and the guide surface 14c of the static pressure guide mechanism is shown in FIG. The two guide surfaces 14a and 14b and the guide surface 14c which are slid and moved in this manner are constituted by triangles or equilateral triangles, and the main axis is provided at the geometric center position thereof.

Since the lower guide surface 14a, 14b is a slide guide mechanism, damping property is ensured. Moreover, since the upper guide surface 14c is a static pressure guide mechanism, the pitching error generated by the lower guide surfaces 14a and 14b can be minimized. In this way, the pitching error can be suppressed. In the present invention, the center of motion synthesized by all the guide surfaces is set to be located at the main axis center. As a drive source in the cutting direction of the main shaft 13, a cylinder, a linear motor, or the like can be used.

3 and 4, when three guide surfaces are provided and two are headstocks, one is provided in contact with the upper surface of the headstock, but the two guide surfaces of the hydrostatic guide mechanism are on the upper side and the slide guide mechanism is on the lower side. One guide surface may be provided.

5 shows another example of the horizontal double head grinding device of the present invention. As shown in FIG. 5, one guide surface member 18 having a plurality of guide surfaces may be used, or two guide surfaces 14c and 14d of the static pressure guide mechanism may be provided on the upper side.

Three guide surfaces are preferable in order not to obstruct the carrying in and taking out of the workpiece. However, if the point can be overcome, the total number of guide surface members 18 may be four or more.

A hydrostatic bearing can be used for the rotating mechanism of the main shaft of the double head grinding device of the present invention. In this case, oil or water can be applied to the static pressure medium, and the precision and rigidity that cannot be obtained by rolling bearings can be ensured. For example, precision rolling is about 1 micrometer in rolling bearings, but 0.01-0.1 micrometer is achieved in hydrostatic bearings.

Although the above has been described with respect to the double head grinding device, it can be used as a double head polishing device similarly when the machining operation member attached to the tip of the main shaft is replaced with a polishing device.

Machining when grinding the workpiece because the center of motion is almost coincident with or coincided with the center position of the main shaft by a plurality of or three guide surfaces for supporting and moving the main shaft in the double head grinding device or the double head grinding device. The bending component of the main shaft can be made small among the reaction forces, thereby making it easy to secure the rigidity against the processing reaction force.

When a static pressure bearing is used as the bearing used for the main shaft, rigidity can be secured and precision can be raised from the micron level to the submicron level.

When a plurality of guide surfaces of the slide guide mechanism and the static pressure guide mechanism are arranged in combination as the guide mechanism of the guide surface, the pitching error can be reduced.

In the case of satisfying the above requirements, the double head grinding device or the double head polishing device of the present invention can be positioned at the level of 10 to 100 nm and at the same time, sufficient rigidity can be secured against the processing reaction force.

Claims (6)

A device for contacting both end faces of a workpiece with a grinding wheel or a polishing cloth mounted on two opposing spindles and simultaneously grinding or polishing the front and back surfaces of the workpiece by rotation of the spindle. A plurality of guide support mechanisms for supporting and moving the main shaft are formed, and the center of motion as the center of the drive member synthesized by the guide surfaces of the plurality of guide support mechanisms is substantially coincident with or completely coincides with the center of the main shaft. Double head grinding and polishing equipment. The double head grinding / polishing apparatus according to claim 1, wherein the guide supporting mechanism is three. The double head grinding / polishing apparatus according to claim 2, wherein two parallel guide supporting mechanisms are disposed on a horizontal plane below the main shaft, and one guide supporting mechanism is disposed above the main shaft in parallel with the guide supporting mechanism. The double head grinding / polishing apparatus according to claim 2, wherein one guide support mechanism is disposed on a horizontal plane below the main shaft, and two parallel guide support mechanisms are disposed above the main shaft in parallel with the guide support mechanism. The two-head grinding / polishing apparatus according to claim 1, wherein the guide supporting mechanism is four. The double head grinding / polishing apparatus according to claim 1, wherein the guide support mechanism disposed above the main shaft is a static pressure guide, and the guide support mechanism disposed below the main shaft is a slide guide.